Question on adjusting rocker arms on hydraulic cam

[65 Coronet]

I have Crane adjustable rockers and the install procedures state:

"On a hydraulic cam rotate the engine until the exhaust valve starts to open. Now, set the intake valve by tightening down the adjusting screw until there is no end play in the pushrod. This is called zero clearance. Now tighten the adjusting screw one complete turn and tighten the lock nut."

My question here is when it says "no end play" does that mean the pushrod should not turn? I would think not as I would think that would collapse the lifter. Should "no end play" be where the pushrod is just set in the lifter and rocker securely and when trying to move the pushrod up and down you can feel the lifter compress and release? I don't want to tighten them down too much.

Thanks,
Mike

 

[lewtot184]

just turn the adjusting screw in to where there isn't any vertical end play between the adjuster and push rod, then go 1 turn more.

 

[65 Coronet]

just turn the adjusting screw in to where there isn't any vertical end play between the adjuster and push rod, then go 1 turn more.

Appreciate the info. I wanted to be sure before I went any further. So I figured this was the best place to ask.

 

[Cranky]

If your adjusters have 32 threads per inch, you will have right at .031" preload after you adjust for no play. Most lifters want more than that but that's what I usually go with too.....like lew said.

 

[440roadrunner]

You must be VERY careful that you adjust for "zero lash" carefully. What that means is that there is no lash with the lifters "pumped clear up" to the top of their travel. It can sometimes be VERY easy to compress them if they were stopped compressed, and then "leak down" as you play with them. Be VERY careful of this. Us a "delicate hand" when feeling until you get used to it. Better to back the rocker way way off to make 'sure" until you get it "down."

The rotational strategy you are using is what we call "EOIC". This is an age old method to insure that you are getting the lifter of the valve you are adjusting on the backside "heel" of the camshaft.

What it means is "When the EXHAUST valve just starts to OPEN, adjust that intake." And, When the INTAKE valve has opened and is very nearly CLOSED again, you adjust that exhaust valve"

As with Cranky, if you figure the threads per inch on the adjusters, this will tell you how far you have preloaded them.

 

[lewtot184]

should be 3/8"-24 thread adjusters. each turn is .0416". all of the newer hydraulic tappets i've measured have .200" plunger travel so .o41" is very safe. retainer to seal/guide clearance may be another issue.

 

[65 Coronet]

You must be VERY careful that you adjust for "zero lash" carefully. What that means is that there is no lash with the lifters "pumped clear up" to the top of their travel. It can sometimes be VERY easy to compress them if they were stopped compressed, and then "leak down" as you play with them. Be VERY careful of this. Us a "delicate hand" when feeling until you get used to it. Better to back the rocker way way off to make 'sure" until you get it "down."

The rotational strategy you are using is what we call "EOIC". This is an age old method to insure that you are getting the lifter of the valve you are adjusting on the backside "heel" of the camshaft.

What it means is "When the EXHAUST valve just starts to OPEN, adjust that intake." And, When the INTAKE valve has opened and is very nearly CLOSED again, you adjust that exhaust valve"

As with Cranky, if you figure the threads per inch on the adjusters, this will tell you how far you have preloaded them.

Thanks for the info. I think when the initial adjustments were done that some of the lifters may have been compressed some when they were set. I will definitely take my time, and figured I'd go through them a couple times. I know it takes more time to do, but I would rather be sure.